我试图使用FreeImage库文件在我project..causes错误 [英] I am trying to use the freeimage library in my project..causes error

问题描述

以下code片段会导致错误的.... logcat中已经连接...我特林从德的java code传递给NDK code，并从那里图像路径I我试图用FreeImage库文件来打开该位图....

  JNIEXPORT无效JNICALL Java_com_example_ImageActivity_brightness（JNIEnv的* ENV，jobject OBJ，的jstring bitmappath，jfloat brightnessValue）
{
    AndroidBitmapInfo信息;    INT RET;
    void *的像素;    如果LString（）（bitmappath！）;       常量jsize LEN = env-＆GT; GetStringUTFLength（bitmappath）;
       为const char * strChars = env-＆GT; GetStringUTFChars（bitmappath，（jboolean *）0）;       性病::字符串结果（strChars，LEN）;       env-＆GT; ReleaseStringUTFChars（bitmappath，strChars）;     FIBITMAP *位= FreeImage_Load（FIF_BMP，Result.c_str（），BMP_DEFAULT）;
     如果（位图）{
    //位图加载成功！
        FreeImage_Unload（位图）;
    }
 

错误日志

 羊群@ QS57：〜/桌面/ Android系统的ImageFilter-NDK $ /家庭/羊群/ ANDROID / Android的NDK-R8 / NDK的构建
编译大拇指：图像处理＆LT; = imageprocessing.c
JNI / imageprocessing.c：在函数'Java_com_example_ImageActivity_brightness：
JNI / imageprocessing.c：77：错误：没有东西结构或联合请求成员的GetStringUTFLength
JNI / imageprocessing.c：78：错误：请求的东西不是一个结构或联合成员GetStringUTFChars
JNI / imageprocessing.c：80：错误：预期出厂前pression'：'令牌
JNI / imageprocessing.c：82：错误：没有东西结构或联合请求成员的ReleaseStringUTFChars
JNI / imageprocessing.c：84：错误：'FIBITMAP'未申报（在一次使用此功能）
JNI / imageprocessing.c：84：错误：（每个未声明的标识符报道只有一次
JNI / imageprocessing.c：84：错误：它出现在每个功能）
JNI / imageprocessing.c：84：错误：未申报的位图（在一次使用此功能）
JNI / imageprocessing.c：84：错误：'FIF_BMP'未申报（在一次使用此功能）
JNI / imageprocessing.c：84：错误：'结果'未声明（第一次使用此功能使用）
JNI / imageprocessing.c：84：错误：'BMP_DEFAULT'未申报（在一次使用此功能）
使：*** [OBJ /本地/ armeabi / OBJ文件/图像处理/ imageprocessing.o]错误1
 

只有当你编译code

解决方案

您正在调用JNI函数的方法是尽可能C ++ code。

如果您需要或想要编译code为C，那么你必须写在JNI下列方式调用：

 常量jsize LEN =（* ENV） -  GT; GetStringUTFLength（ENV，bitmappath）;
为const char * strChars =（* ENV） -  GT; GetStringUTFChars（ENV，bitmappath，（jboolean *）0）;
 

The following code snippet causes error....the logcat has been attached...I am tring to pass the image path from teh java code to the NDK code and from there I am trying to open the bitmap using FreeImage library....

JNIEXPORT void JNICALL Java_com_example_ImageActivity_brightness(JNIEnv* env, jobject  obj, jstring bitmappath, jfloat brightnessValue)
{
    AndroidBitmapInfo  info;

    int ret;
    void* pixels;

    if ( !bitmappath ) LString();

       const jsize len      = env->GetStringUTFLength(bitmappath);
       const char* strChars = env->GetStringUTFChars(bitmappath, (jboolean *)0);

       std::string Result(strChars, len);

       env->ReleaseStringUTFChars(bitmappath, strChars);

     FIBITMAP *bitmap = FreeImage_Load(FIF_BMP,Result.c_str(), BMP_DEFAULT);
     if (bitmap) {
    // bitmap successfully loaded!
        FreeImage_Unload(bitmap);
    }

Error log

flock@QS57:~/Desktop/android-imagefilter-ndk$ /home/flock/ANDROID/android-ndk-r8/ndk-build
Compile thumb  : imageprocessing <= imageprocessing.c
jni/imageprocessing.c: In function 'Java_com_example_ImageActivity_brightness':
jni/imageprocessing.c:77: error: request for member 'GetStringUTFLength' in something not a structure or union
jni/imageprocessing.c:78: error: request for member 'GetStringUTFChars' in something not a structure or union
jni/imageprocessing.c:80: error: expected expression before ':' token
jni/imageprocessing.c:82: error: request for member 'ReleaseStringUTFChars' in something not a structure or union
jni/imageprocessing.c:84: error: 'FIBITMAP' undeclared (first use in this function)
jni/imageprocessing.c:84: error: (Each undeclared identifier is reported only once
jni/imageprocessing.c:84: error: for each function it appears in.)
jni/imageprocessing.c:84: error: 'bitmap' undeclared (first use in this function)
jni/imageprocessing.c:84: error: 'FIF_BMP' undeclared (first use in this function)
jni/imageprocessing.c:84: error: 'Result' undeclared (first use in this function)
jni/imageprocessing.c:84: error: 'BMP_DEFAULT' undeclared (first use in this function)
make: *** [obj/local/armeabi/objs/imageprocessing/imageprocessing.o] Error 1

解决方案

The way you are calling JNI functions is possible only if you compile code as C++ code.

If you need or want to compile code as C then you must write JNI calls in following way:

const jsize len      = (*env)->GetStringUTFLength(env, bitmappath);
const char* strChars = (*env)->GetStringUTFChars(env, bitmappath, (jboolean *)0);

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